The Children's Oncology Group (COG) is the largest childhood cancer research organization in the world and encompasses 216 pediatric cancer programs with a mission to cure and prevent childhood and adolescent cancer through scientific discovery and compassionate care. The COG was formed from the merger of four legacy pediatric cooperative groups in 2000. The COG Community Clinical Oncology Program (CCOP) Research Base was funded in 2002 as a Treatment and Cancer Prevention and Control CCOP Research Base. The COG CCOP Research Base supports 19 CCOPs and 7 Minority-Based CCOPs for participation on innovative clinical and translational research studies for cancer treatment, prevention and control. The involvement of community-based pediatric oncologists and other health professionals in the research mission of the COG is pivotal. CCOPs provide an important mechanism to evaluate advanced treatments administered in community settings and broaden the population-base for protocol participation. The COG makes available to CCOPs/Minority-Based CCOPs current treatment protocols with access to investigational agents and special centralized reference laboratories, quality assurance infrastructure and statistical support, thus promoting high quality cancer care for young persons treated in community settings. The COG provides continuing training and support for CCOP personnel and ensures that all CCOPs maintain high quality assurance standards for membership, accrual, and institutional performance. COG conducts clinical trials to define optimal treatments for children and adolescents with cancer, with a focus on addressing the unique needs of children afflicted with cancer. The Cancer Control Committee develops studies that focus on identifying, preventing or ameliorating treatment-related sequelae and improving the quality of life for children and adolescents with cancer and their families.